"A polite letter was sent to 35,000 such persons in the first lot. Two weeks ago we have sent letters, another lot of 35,000 persons. Today letters are being issued to a third lot of 35,000 persons," he told reporters here.

The Minister assured that the I-T department would take a benign view of assessees volunteering to file returns and clear their dues and interest.

"The tax authorities can take a benign view and waive the penalty. They have done so in numerous cases in the past. This is your opportunity to file your returns, pay your tax and interest, if any, and apply for waiver of penalty," he said urging the assessees to pay advance tax by tomorrow.

The last date for paying the final instalment of advance tax is March 15 for corporates as well as individuals.

Chidambaram said the steps taken by the tax department to check evasion is reaping results as 10,000 assessees, of the 70,000 to whom notices were sent, have disclosed their income and filed taxes on receiving the letter.

"These letters have had salutary effect. Over 10,000 recipients, of the first two lots of letters, have filed their returns and paid their tax dues," Chidambaram said.

The revenue department is tapping each and every source of revenue to achieve the Rs 5.65 lakh crore collection target under the direct taxes category for this fiscal that ends on March 31.